NOTE: The knob at the front of the seat to control the TPH drop rate is often secured with a set screw - if you don't back that out before you try to turn the valve, the knob will strip off the shaft and you'll be screwed. Use a flashlight and a wire brush to make sure you're located that set screw (if any) and back it out first. When that valve is closed all the way (screwed in), it diverts the flow of hydraulic fluid from the TPH to the rear remote(s). As you open it, it allows the fluid to go to the TPH and the further open it is the faster the TPH arms will drop. The arms may not drop with no implement to provide weight, but you can stand on them to push them down. Unless the valve is very close to being closed, it won't have much effect on how fast the TPH arms raise.